Question

The peptide that gives positive ceric ammonium nitrate and carbylamine test is:
A.Lys-Asp
B.Ser-Lys
C.Gln-Asp
D.Asp-Gln

Answer 1

Peptides are basically a small or short chain with anywhere between two to fifty amino acids. These small chains are held together by peptide bonds, hence the name.

Complete step by step answer:
The Carbylamine test is basically a method for detecting or determining primary amines given in the present compounds, by heating up the given substance with chloroform in a basic solution. The test shows positive results for the presence of a primary amine, by emitting a characteristic foul smell, which is caused by the release of isocyanide. The general carbylamine reaction can be represented as follows:
$R - N{H_2} + CHC{l_3} + 3KOH \to RNC + 3KCl + 3{H_2}O$
Ceric ammonium nitrate test is used for identifying the existence of alcoholic functional groups. In this test, a sample of the given compound is dissolved in an appropriate solvent. If the solution turns red, then the test result is positive.
The given peptides are:
Lysine (Lys)-

Aspartic acid (Asp)-

Glutamine (Gln) –

Serine (Ser) –

We can see that as a combination, only serine and lysine would be able to give a positive result for both the tests due to the presence of -OH and - $N{H_2}$ functional groups.

Hence, Option B is the correct option.

Note:
A peptide bond is formed when the carboxyl group of one molecule reacts with the amino group of another molecule releasing a molecule of water.